偏移对象 （.NET）

偏移对象会创建一个与原始对象具有指定偏移距离的新对象。您可以偏移圆弧、圆、椭圆、直线、轻量级折线、折线、样条和 x线。

若要偏移对象，请使用为该对象提供的方法。该函数需要偏移对象距离的正数值或负数值。如果距离为负数，AutoCAD 会将其解释为偏移以生成“较小”曲线（即，对于圆弧，它将偏移到小于起始曲线半径的给定距离的半径）。如果“较小”没有含义，则AutoCAD将沿较小的X，Y，Z WCS坐标方向偏移。GetOffsetCurves

对于许多对象，此操作的结果将是一条新曲线（可能与原始曲线的类型不同）。例如，偏移椭圆将导致样条曲线，因为结果确实符合椭圆的方程。在某些情况下，偏移结果可能需要是几条曲线。因此，该函数返回一个对象，该对象包含通过偏移曲线创建的所有对象。对于创建的每个对象，需要对返回的对象进行迭代，然后将其追加到图形数据库中。DBObjectCollectionDBObjectCollection

偏移折线

本示例创建一条轻量级折线，然后对其进行偏移。

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
 
<CommandMethod("OffsetObject")> _
Public Sub OffsetObject()
    '' Get the current document and database
    Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
    Dim acCurDb As Database = acDoc.Database

    '' Start a transaction
    Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

        '' Open the Block table for read
        Dim acBlkTbl As BlockTable
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _
                                     OpenMode.ForRead)

        '' Open the Block table record Model space for write
        Dim acBlkTblRec As BlockTableRecord
        acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
                                        OpenMode.ForWrite)

        '' Create a lightweight polyline
        Using acPoly As Polyline = New Polyline()
            acPoly.AddVertexAt(0, New Point2d(1, 1), 0, 0, 0)
            acPoly.AddVertexAt(1, New Point2d(1, 2), 0, 0, 0)
            acPoly.AddVertexAt(2, New Point2d(2, 2), 0, 0, 0)
            acPoly.AddVertexAt(3, New Point2d(3, 2), 0, 0, 0)
            acPoly.AddVertexAt(4, New Point2d(4, 4), 0, 0, 0)
            acPoly.AddVertexAt(5, New Point2d(4, 1), 0, 0, 0)

            '' Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly)
            acTrans.AddNewlyCreatedDBObject(acPoly, True)

            '' Offset the polyline a given distance
            Dim acDbObjColl As DBObjectCollection = acPoly.GetOffsetCurves(0.25)

            '' Step through the new objects created
            For Each acEnt As Entity In acDbObjColl
                '' Add each offset object
                acBlkTblRec.AppendEntity(acEnt)
                acTrans.AddNewlyCreatedDBObject(acEnt, True)
            Next
        End Using

        '' Save the new objects to the database
        acTrans.Commit()
    End Using
End Sub

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
 
[CommandMethod("OffsetObject")]
public static void OffsetObject()
{
    // Get the current document and database
    Document acDoc = Application.DocumentManager.MdiActiveDocument;
    Database acCurDb = acDoc.Database;

    // Start a transaction
    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Block table for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,
                                        OpenMode.ForRead) as BlockTable;

        // Open the Block table record Model space for write
        BlockTableRecord acBlkTblRec;
        acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                                        OpenMode.ForWrite) as BlockTableRecord;

        // Create a lightweight polyline
        using (Polyline acPoly = new Polyline())
        {
            acPoly.AddVertexAt(0, new Point2d(1, 1), 0, 0, 0);
            acPoly.AddVertexAt(1, new Point2d(1, 2), 0, 0, 0);
            acPoly.AddVertexAt(2, new Point2d(2, 2), 0, 0, 0);
            acPoly.AddVertexAt(3, new Point2d(3, 2), 0, 0, 0);
            acPoly.AddVertexAt(4, new Point2d(4, 4), 0, 0, 0);
            acPoly.AddVertexAt(5, new Point2d(4, 1), 0, 0, 0);

            // Add the new object to the block table record and the transaction
            acBlkTblRec.AppendEntity(acPoly);
            acTrans.AddNewlyCreatedDBObject(acPoly, true);

            // Offset the polyline a given distance
            DBObjectCollection acDbObjColl = acPoly.GetOffsetCurves(0.25);

            // Step through the new objects created
            foreach (Entity acEnt in acDbObjColl)
            {
                // Add each offset object
                acBlkTblRec.AppendEntity(acEnt);
                acTrans.AddNewlyCreatedDBObject(acEnt, true);
            }
        }

        // Save the new objects to the database
        acTrans.Commit();
    }
}

Sub OffsetObject()
    ' Create the polyline
    Dim plineObj As AcadLWPolyline
    Dim points(0 To 11) As Double
    points(0) = 1: points(1) = 1
    points(2) = 1: points(3) = 2
    points(4) = 2: points(5) = 2
    points(6) = 3: points(7) = 2
    points(8) = 4: points(9) = 4
    points(10) = 4: points(11) = 1
    Set plineObj = ThisDrawing.ModelSpace. _
                                    AddLightWeightPolyline(points)
    plineObj.Closed = True
    ZoomAll
 
    ' Offset the polyline
    Dim offsetObj As Variant
    offsetObj = plineObj.Offset(0.25)
 
    ZoomAll
End Sub